7,470 research outputs found
The preservation of quartz grain surface textures following vehicle fire and their use in forensic enquiry
During a terrorist trial, dispute arose as to whether the temperature produced in a car fire was sufficient to destroy quartz grain surface textures. A series of seven sequential experiments showed that the temperature for quartz surface texture modification/destruction and the production of vugs, vesicles and glassy precipitation ('snowdrifting') occurred at 1200 degrees C under normal atmospheric conditions. By adding a number of man-made and natural substances, it was found that only the presence of salts depressed this modification temperature (to 900 degrees C). Experiments to determine the temperature of fire in a car indicated that the maximum temperature produced under natural conditions (810 degrees C) was insufficient to affect the quartz grain Surface textures. These results confirm the use of surface texture analysis of quartz grains recovered from the remains of cars Subjected to fire and their use as a forensic indicator. (C) 2008 Forensic Science Society. Published by Elsevier Ireland Ltd. All rights reserved
Material properties of the heel fat pad across strain rates
The complex structural and material behaviour of the human heel fat pad determines the transmission of plantar loading to the lower limb across a wide range of loading scenarios; from locomotion to injurious incidents. The aim of this study was to quantify the hyper-viscoelastic material properties of the human heel fat pad across strains and strain rates. An inverse finite element (FE) optimisation algorithm was developed and used, in conjunction with quasi-static and dynamic tests performed to five cadaveric heel specimens, to derive specimen-specific and mean hyper-viscoelastic material models able to predict accurately the response of the tissue at compressive loading of strain rates up to 150 s−1. The mean behaviour was expressed by the quasi-linear viscoelastic (QLV) material formulation, combining the Yeoh material model (C10=0.1MPa, C30=7MPa, K=2GPa) and Prony׳s terms (A1=0.06, A2=0.77, A3=0.02 for τ1=1ms, τ2=10ms, τ3=10s). These new data help to understand better the functional anatomy and pathophysiology of the foot and ankle, develop biomimetic materials for tissue reconstruction, design of shoe, insole, and foot and ankle orthoses, and improve the predictive ability of computational models of the foot and ankle used to simulate daily activities or predict injuries at high rate injurious incidents such as road traffic accidents and underbody blast
Current status of MCNP6 as a simulation tool useful for space and accelerator applications
For the past several years, a major effort has been undertaken at Los Alamos
National Laboratory (LANL) to develop the transport code MCNP6, the latest LANL
Monte-Carlo transport code representing a merger and improvement of MCNP5 and
MCNPX. We emphasize a description of the latest developments of MCNP6 at higher
energies to improve its reliability in calculating rare-isotope production,
high-energy cumulative particle production, and a gamut of reactions important
for space-radiation shielding, cosmic-ray propagation, and accelerator
applications. We present several examples of validation and verification of
MCNP6 compared to a wide variety of intermediate- and high-energy experimental
data on reactions induced by photons, mesons, nucleons, and nuclei at energies
from tens of MeV to about 1 TeV/nucleon, and compare to results from other
modern simulation tools.Comment: 4 pages, 3 figures, Proc. 11th Conference on the Intersections of
Particle and Nuclear Physics (CIPANP 2012), St. Petersburg, FL, May 28 - June
3, 201
A Positive Library Experience for International Students? Results from a Business Librarians Association survey
The theme of the annual Business Librarians Association BLA) three-day conference held at Stirling Management Centre during summer 2012 was ‘Going global? Challenges of internationalisation’. Business schools in the UK attract large numbers of international students,2 and the conference
aimed to explore how business librarians can help provide a positive experience for international students.
To support this theme, three business librarians, Stephen Bull from University of Birmingham,Stephanie Allen from University of Worcester and Alison Lahlafi from Sheffield Hallam University, collaborated on a survey of BLA members services to international students
3D shape reconstruction of the femur from planar X-ray images using statistical shape and appearance models
Major trauma is a condition that can result in severe bone damage. Customised orthopaedic reconstruction allows for limb salvage surgery and helps to restore joint alignment. For the best possible outcome three dimensional (3D) medical imaging is necessary, but its availability and access, especially in developing countries, can be challenging. In this study, 3D bone shapes of the femur reconstructed from planar radiographs representing bone defects were evaluated for use in orthopaedic surgery. Statistical shape and appearance models generated from 40 cadaveric X-ray computed tomography (CT) images were used to reconstruct 3D bone shapes. The reconstruction simulated bone defects of between 0% and 50% of the whole bone, and the prediction accuracy using anterior–posterior (AP) and anterior–posterior/medial–lateral (AP/ML) X-rays were compared. As error metrics for the comparison, measures evaluating the distance between contour lines of the projections as well as a measure comparing similarities in image intensities were used. The results were evaluated using the root-mean-square distance for surface error as well as differences in commonly used anatomical measures, including bow, femoral neck, diaphyseal–condylar and version angles between reconstructed surfaces from the shape model and the intact shape reconstructed from the CT image. The reconstructions had average surface errors between 1.59 and 3.59 mm with reconstructions using the contour error metric from the AP/ML directions being the most accurate. Predictions of bow and femoral neck angles were well below the clinical threshold accuracy of 3°, diaphyseal–condylar angles were around the threshold of 3° and only version angle predictions of between 5.3° and 9.3° were above the clinical threshold, but below the range reported in clinical practice using computer navigation (i.e., 17° internal to 15° external rotation). This study shows that the reconstructions from partly available planar images using statistical shape and appearance models had an accuracy which would support their potential use in orthopaedic reconstruction
Progress report on a new search for free e/3 quarks in the cores of 10(15) - 10(16) eV air showers
The Leeds 3 sq m Wilson cloud chamber is being used in a new search for free e/3 quarks close to the axes of 10 to the 15th power - 10 to the 16th power eV air showers. A ratio trigger circuit is used to detect the incidence of air shower cores; the position of the shower center and the axis direction are determined from photographs of current-limited spark chambers. It is thus possible, for the first time, to know where we have looked for quarks in air showers and to select for scanning only those cloud chamber photographs where we have good evidence that the shower axis was close to the chamber. 250 g/sq cm of lead/concrete absorber above the cloud chamber serve to reduce particle densities and make a quark search possible very close to the shower axes. The current status of the search is given
QuizMap: Open social student modeling and adaptive navigation support with TreeMaps
In this paper, we present a novel approach to integrate social adaptive navigation support for self-assessment questions with an open student model using QuizMap, a TreeMap-based interface. By exposing student model in contrast to student peers and the whole class, QuizMap attempts to provide social guidance and increase student performance. The paper explains the nature of the QuizMap approach and its implementation in the context of self-assessment questions for Java programming. It also presents the design of a semester-long classroom study that we ran to evaluate QuizMap and reports the evaluation results. © 2011 Springer-Verlag Berlin Heidelberg
Progressor: Social navigation support through open social student modeling
The increased volumes of online learning content have produced two problems: how to help students to find the most appropriate resources and how to engage them in using these resources. Personalized and social learning have been suggested as potential ways to address these problems. Our work presented in this paper combines the ideas of personalized and social learning in the context of educational hypermedia. We introduce Progressor, an innovative Web-based tool based on the concepts of social navigation and open student modeling that helps students to find the most relevant resources in a large collection of parameterized self-assessment questions on Java programming. We have evaluated Progressor in a semester-long classroom study, the results of which are presented in this paper. The study confirmed the impact of personalized social navigation support provided by the system in the target context. The interface encouraged students to explore more topics attempting more questions and achieving higher success rates in answering them. A deeper analysis of the social navigation support mechanism revealed that the top students successfully led the way to discovering most relevant resources by creating clear pathways for weaker students. © 2013 Taylor and Francis Group, LLC
Recent Developments in Forest Products Trade between Russia and China: Potential Production, Processing, Consumption and Trade Scenarios
China has a very significant role in the global timber market and this has significant ramifications for forests, forest livelihoods and the structure of forest industries around the world. In this report we will focus on possible future trends in the forest products-processing, consumption and trade between China and its main suppliers, with a particular focus on Eastern Russia (Siberia and the Russian Far East). The data used for the report preceded the global economic downturn which started in 2008. While the current downturn will likely have an impact on regional supply, processing, consumption and trade in the short-term, in the long-term it is expected that the global economy will recover and these trends will resume in a predictable fashion based on the data incorporated into the scenarios presented in this report. The International Forest and Forest Products [IFFP] trade model was used as a modeling tool to undertake the analysis. It includes a model of the global industrial forest estate
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